# 利用ellipse 和 rectangle 画图

if __name__ == '__main__':
    from tkinter import *

    canvas = Canvas(width=400, height=600, bg='white')
    left = 20
    right = 50
    top = 50
    num = 15
    for i in range(num):
        canvas.create_oval(250 - right, 250 - left, 250 + right, 250 + left)
        canvas.create_oval(250 - 20, 250 - top, 250 + 20, 250 + top)
        canvas.create_rectangle(20 - 2 * i, 20 - 2 * i, 10 * (i + 2), 10 * (i + 2))
        right += 5
        left += 5
        top += 10

    canvas.pack()
    mainloop()
